Love the idea. This is exactly what the hobby needs and I'll contribute whatever I can.
The only problem I see is, as mentioned, it's probably better to describe what makes a particular autograph "good" versus just posting a photo. Not sure how many to the "Top Guns" would share that hard learned knowledge.
Also, I remember discussing this with an esteemed member here a while back and we agreed that to do something like this really well would be about the size of a dozen volume set
It's worth a shot.